Abstract: The automatic programming of complex space curved surface welding robots is fundamental to achieving high-frequency, high-precision automatic welding. To maintain constant welding speed and torch pose during space surface welding, a motion planning method suitable for complex space surface welding robots was proposed. NURBS curves were used to smooth and approximate the space trajectory described by three-dimensional point clouds. The kinematic model of a multi-degree-of-freedom welding system was established, and inverse kinematics were solved. Finally, a complete automatic programming system for complex spatial curved welding robots was developed based on the above research. A lapel shaper was used as an example to perform automatic programming and welding experiments with a complex space curved surface welding robot. The results show that the proposed motion planning method and automatic programming system for complex space curved surface welding robots can successfully complete welding tasks with stable motion and good welding trajectory accuracy.